Thanks, Andavari. Yes you're rigth, it works for all single MS Office apps, but not for the common Office directory.
So there are two of us who noticed this. I must say I could'nt believe it, as this lack is so basic ...
Windows XP / CcCleaner v1.35.424 (but same with v1.34)
Everything works fine except that the MS Office 2003 "Recent Files" directory does'nt get cleaned, although the box Application/Office 2003 is checked.
I have to add manualy the cleaning of custom directory "C:/Document and Settings/<User>/Application Data/Microsoft/Office/Recent/".
Any explanation ?